Theftproof ignition device



May 6, 1958 T. DIEHL THEFTPROOF IGNITION DEVICE Filed June s, 1955 IINVENTOR TheodorelZDie/zl United States Patent THEFTPROOF IGNITION DEVICE Theodore E. Diehl, Baltimore, Md.

Application June 3, 1955, Serial No. 512,969

6 Claims. (Cl. 123-1465) This invention relates to an ignition lock system or motor powered conveyances such as automobiles, boats and the like, and more particularly to a means for preventing the unauthorized use thereof by bridging around the ignition lock.

In the case of many present day ignition systems, unauthorized use is possible by bridging around or shorting out the usual key operated ignition lock, thus enabling the motor to be started.

It is an object of this invention to prevent unauthorized use of a motor powered conveying means.

A further object of this invention is to safeguard the ignition system of a motor powered conveying means by providing a device which prevents the starting of the motor without the use of a proper ignition key.

Another object of this invention is to provide means for guarding the distributor condenser circuit so that the condenser is not in the circuit unless the ignition key is in the lock and the lock cylinder is rotated to ignition operating position.

An additional object of this invention is to provide means preventing access to the condenser unless the ignition key is in the lock and the lock cylinder is rotated to ignition operating position.

These and other objects will appear in connection with the following specification taken with the accompanying drawings forming a part thereof.

In the drawings:

Fig. 1 is a longitudinal section through an ignition lock switch housing showing my invention applied thereto and showing the parts in the non-operative position;

Fig. 2 is a section substantially in the line 2-2 of Fig. 1;

Fig. 3 is a section substantially on the line 3-3 of Fig. 1;

Fig. 4 is a section substantially on the line 44 of Fig. 1;

Fig. 5 is a partial view showing the parts in their operative position, and

Fig. 6 is a wiring diagram.

In the drawings, like characters of reference indicate like parts throughout the several figures.

The device illustrated in Fig. l is a combination condenser housing and ignition lock housing which is attached to the dash board 10 of a motor powered conveying means such as an automobile, boat or the like. A lock housing 12 is attached to the dash board 10 through an opening 14 by means of a nut or other fastening means 16. The housing 12 has a cylindrical bore 18 to accommodate a conventional type lock cylinder 20 having tumblers, not illustrated, adapted to cooperate with tumblers 22 in radial openings 24. The tumblers 22 are urged toward the cylinder 20 by springs 26 and 2 Mounted in the cylinder is the ignition switch contact 30 adapted to close the circuit from the battery 34 to the ignition coil 32, including insulated wire 31. A cup shaped condenser housing 36 is attached toithe' rear end of the housing 12 by bayonet joints comprising lugs 38 on the-housing 12- engaging in slots 40 on the housing 36.

A cylindrical bore 42 in the housing 36 .is lined with a cup shaped cylindrical insulating member 44. A metallic washer 46 is placed at the outer end of the insulating member 44 and is connected by insulated wire 48 to the low voltage breaker in' the distributor for the ignition system with which it isto be'u'sed. A condenser 50 is placed in the insulating cup. 44 and is urged toward the forward end of the housing 36 by a spring 52, which also makes contact with one terminal of the condenser through one end thereof and with the wire 48" through the washer 46. At the forward end of the insulating member 44 is an insulating washer 54, and a retaining ring 56 to retain the condenser 50 therein.

The condenser 50 is provided with another terminal 60 projecting through an opening- 62 in the washer 54.

A slot 64 is provided in the cooperating ends ofthe housings 12 and 36, to accommodate a switch actuating member 66. The actuating member 66: is somewhat U- shaped in cross-section and has a lower end 67 engaging below the cam lug, 28 against which the member 66 is urged by a spring 68 which engages a. boss 70 on the housing 36, and the lower portion 67 of the actuator 66. The actuator 66 carries a spring contactmember 72 adapted, under certain conditions, to engage the termina1 60' on the condenser 50.

The upper end 69' of the actuator 66 extends into a recess 71 in the housing 36 when the elements are in locked position, note Figs; 1 and 3, thus preventing rotation of the housing 36 in relation to the housing 12 to prevent the removal of the condenser 50 without the insertion of a proper key and rotation of the cylinder 20.

The operation of my device will now be explained and is as follows: Insertion of a proper key in the slot 74 of the cylinder 20 operates the tumblers 22 to permit rotation of the cylinder 20. The rotation of the cylinder 20 closes the ignition circuit at 30. Current from the battery 34 flows through wire 76, ammeter A, wire 78 to the primary of coil 32 and wire 80 to the distributor 82. As contact is made by the breaker 84 the current returns to the battery 34 through the ground return G of the machine frame. Breaking of the gap at 84 causes the magnetic flux in the coil 32 to collapse. This sets up an E. M. F. in the secondary of coil 32 which is led through wire 86 to the spark distributor, and at the same time sets up an E. M. F. in the primary of the coil which charges the condenser in the customary manner.

The condenser 50 is essential as a part of the ignition circuit, as is well known, to reduce the sparking at the gap 84 to avoid burning or sticking of the breaker points. The condenser also functions upon the discharge through the coil 32 to provide the kick or high E. M. F. in the coil 32, thus producing the high tension, high frequency E. M. F. necessary for proper sparking at the plugs.

Rotation of the cylinder 20 also causes, by engagement of cam lug 28 with the lower end 67 of the actuator 66, movement of said actuator against tension of the spring 68. Such movement brings the spring contact 72 into engagement with the terminal 60 on the condenser 48, see Fig. 5, completing the condenser circuit for proper functioning of the ignition system.

In the locked position shown in Figs. 1 and 3, the

actuator 66 prevents rotation of the housing 36 to remove.

same. In the unlocked position of Fig. 5, the actuator 66 frees the housing 36 to be removed for replacement of the condenser.-

- Since the condenser can not be connected into the circuit without using a proper key'and rotating the lock cylinder to move the actuator 66, bridging or shorting out the ignition switch will not enable'an unauthorized starting of the motor. This should effectually prevent casual theft of a vehicle on which my invention is used, since rewiring the ignition to insert a condenser properly in thecircuit may consume more time than would be available to a casual thief, and also might draw attentionto his operations. ,My invention is, therefore, a theft preventer'or discourager.

While specific examples have been given, it is to be understood that many changes may be made by one skilled in the art within the purview of the appended claims.

a I claim:

1. In a theft prevention device fora motor vehicle ignition system having a distributor including a breaker and having a lockable ignition switch and a lock therefor having a housing and including a lock cylinder within the lock housing, the improvement comprising a condenser housing removably attached to the lock housing, a condenser within the condenser housing and having one terminal adapted to be connected "to the breaker means of the ignition distributor and having a secondterminal adjacent said lock i cylinder and accessible only from within the condenser housing, means operated by the lock cylinder for engaging the second terminal to ground said terminal to the lock housing.

2; The structure of claim 1 in which the lock housing and the condenser housing are removably connected together as a unit and in which the means connected to the lock cylinder for grounding the second condenser terminal also locks the condenser housing against separa- 4 tion from the lock housing when theignition switch is locked. v

3. The subject matter of claim 2 in which the adjacent parts of the condenser housing and the lock housing are provided with mating slots and lugs and in which the means engaging the second condenser terminal is an actuator provided with a contact for engaging the second condenser terminal to ground same through the lock.

4. The structure of claim 3 wherein motion of the actuator to grounding position releases the housing for removal of the condenser when desired.

5. The subject matter of claim 1 wherein the means connected with the lock cylinder engageable with the grounding means comprises a cam lug on the end of the lock cylinder and a substantially U-shaped member embracing said cam lug and slida'bly mounted in the condenser housing, spring means urging said member towards said cam lug and a spring contact mounted on said member engageable with the second condenser terminal on movement of said member .to unlock the ignition switch.

6. A theft prevention device for use in an ignition system for an internal combustion engine, said system including a distributor having a circuit breaker, a housing, an ignition switch lock in the housing, a condenser in the housing, one terminal of the condenser being connectedputside the housing to the circuit breaker of the distributor, a second terminal being within the housing, means operated by the switch lock for grounding said second terminal within the housing.

References Cited in the file of this patent UNITED STATES PATENTS 2,461,196 Brown Feb. 8, 1949 FOREIGN PATENTS 321,247 Great Britain Nov. 7, 1929 355,586 Great Britain Aug. 27, 1931 

